Field
The present disclosure is generally related to a tape rule assembly.
Description of Related Art
A typical tape rule assembly includes an elongated metal rule blade that is mounted on a reel rotatably disposed within a housing. The rule blade is retracted into the housing for storage by coiling it about the reel. To measure a work-piece, a length of the rule blade is pulled out of the housing to span the distance to be measured and the blade or hook is held against the work-piece so that gradation lines and numbers printed on the blade can be read against a point on the work-piece. To measure a distance between two objects or surfaces, an end hook at the free end of the blade may be temporarily secured or placed against an object or surface. The hook includes a hook portion that extends downwardly at an essentially right angle from a mounting portion of the hook that is mounted on the end of the blade. When the hook of the retracted blade is at the opening, the downwardly extending hook portion extends below a bottom end surface of the housing assembly adjacent the opening. In addition, long tape assemblies are known in which an elongated tape is wound on a reel and can be extended to measure distances. These long tape assemblies may also utilize an end hook.
It is convenient for the user to have the hook portion of the blade extend below the bottom surface of the housing assembly, so that, for example, the retracted blade can be easily withdrawn from the housing assembly by grasping the hook portion or hooking the hook portion over an edge or corner of an object or workpiece. The hook aids the tape assembly user when taking a measurement by securing the free end of the blade while the measurement is taken. The hook is precisely manufactured and mounted to assure accurate measurements.
In instances where a tape rule assembly is dropped, the hook portion may be impacted by contact with the floor or ground or other surface. For example, FIGS. 21A and 21B show examples of how a hook portion of a tape rule assembly can be impacted by a substantially vertical force F or a substantially angular force F2 when a tape rule assembly contacts and hits the ground G. The impact by such force F and/or force F2 can cause damage to the hook portion.
If the hook is damaged by being bent so that the hook portion is misshapen or no longer at an essentially right angle with the free end of the blade, a measurement read while securing the blade with the hook portion may not be accurate. Because a portion of the blade hook extends below the bottom end surface of the housing assembly when the blade is fully retracted, the hook is especially vulnerable to damage if the tape assembly is dropped or otherwise impacted when the blade is retracted under the force of the tape assembly spring. If the lower edge of the hook portion is impacted in a direction that causes the free end to move upwardly with respect to the housing assembly, the hook portion may permanently bend relative to the mounting portion if, during impact, the mounting portion of the hook is prevented by downwardly facing surfaces on the housing assembly that define the housing assembly opening from moving upwardly a sufficient distance with respect to the opening. Thus, the size (e.g., height) of the opening can impact the amount of damage to the blade hook during impact as discussed in U.S. Pat. No. 6,282,808, hereby incorporated by reference in its entirety.